package com.ks.test.thread;

import java.util.concurrent.CountDownLatch;


/**
 * 并行任务处理工具
 * 
 * @author zengyuanjun
 *
 */
public class MultiParallelThreadHandler extends AbstractMultiParallelThreadHandler {

    /**
     * 无参构造器
     */
    public MultiParallelThreadHandler() {
        super();
    }

    /**
     * 根据任务数量运行任务
     */
    @Override
    public void run() throws ChildThreadException {
        if (null == taskList || taskList.size() == 0) {
            return;
        } else if (taskList.size() == 1) {
            runWithoutNewThread();
        } else if (taskList.size() > 1) {
            runInNewThread();
        }
    }

    /**
     * 新建线程运行任务
     * 
     * @throws ChildThreadException
     */
    private void runInNewThread() throws ChildThreadException {
        childLatch = new CountDownLatch(taskList.size());
        childThreadException.clearExceptionList();
        for (Runnable task : taskList) {
            invoke(new MultiParallelRunnable(new MultiParallelContext(task, childLatch, childThreadException)));
        }
        taskList.clear();
        try {
            childLatch.await();
        } catch (InterruptedException e) {
            childThreadException.addException(e);
        }
        throwChildExceptionIfRequired();
    }

    /**
     * 默认线程执行方法
     * 
     * @param command
     */
    protected void invoke(Runnable command) {
        if(command.getClass().isAssignableFrom(Thread.class)){
            Thread.class.cast(command).start();
        }else{
            new Thread(command).start();
        }
    }

    /**
     * 在当前线程中直接运行
     * 
     * @throws ChildThreadException
     */
    private void runWithoutNewThread() throws ChildThreadException {
        try {
            taskList.get(0).run();
        } catch (Exception e) {
            childThreadException.addException(e);
        }
        throwChildExceptionIfRequired();
    }

    /**
     * 根据需要抛出子线程异常
     * 
     * @throws ChildThreadException
     */
    private void throwChildExceptionIfRequired() throws ChildThreadException {
        if (childThreadException.hasException()) {
            childExceptionHandler(childThreadException);
        }
    }

    /**
     * 默认抛出子线程异常
     * @param e 
     * @throws ChildThreadException
     */
    protected void childExceptionHandler(ChildThreadException e) throws ChildThreadException {
        throw e;
    }

}